Among HD, a high percentage of PHA-stimulated CD25+CD134+ in both T cell subsets was observed, with frequencies of CD4+ T cells (median 37.8%, IQR 31.6–46.5%) greater than those of CD8+ T cells (median 19.7%, IQR 12.1–38.1%; p = 0.01). The gene discussed is IL2RA; the disease is Huntington disease.